The present invention is directed to a method and apparatus to monitor the performance of an industrial control system or the like and particularly to a performance monitoring system that does not interfere with the operation of the monitored system or system display and that provides an indication of real-time operation of the monitored system.
The industrial controller of the monitored system communicates control signals to the individual devices or equipment such as motors, fans, blowers, pumps, valves, relays, and switches to generate the desired procedure. Frequently, the industrial controller includes an operator interface, such as a personal computer having a display and user input such as a keyboard and/or mouse. The operator interface facilitates operator interaction and monitoring of the industrial controller and operation of the monitored system. The display of the operator interface is generally configured to generate a schematic representation of the equipment and/or process being operated by the industrial controller. Accurate and timely representation of the condition of the equipment on the operator is important to operator interaction with the industrial controller.
Commonly, confirmation of an operating condition of the controlled equipment is confirmed through external monitoring or analysis of the process signals generated by the industrial controller. Such monitoring is often performed by a service technician, or other skilled personnel, connecting to or modifying the control system to acquire and monitor the signals generated by the industrial controller and communicated to the process equipment. Due to the labor and expense associated with such performance monitoring procedures, such monitoring may occur when a process error has already occurred.
Such monitoring procedures may also affect the real-time operation of the industrial controller. That is, embedded instructions configured to generate the desired monitoring signals, consume system resources that could otherwise be utilized for operation of the process equipment. Such monitoring procedures may also change or interfere with the operation of the industrial controller as compared to operation of the industrial controller when no performance monitoring is being conducted. As such, such performance monitoring systems may not accurately reflect non-monitored system performance and may be incapable of accurately determining the operating efficiency of the industrial controller. Such industrial controller performance monitoring systems are also incapable of confirming actual communication of a process condition signal to an operator.
Where the process display depicts a schematic representation of the process equipment, even though an industrial controller signal reflects communication of a corresponding signal to the display, the generation of the industrial controller signal does not confirm that a corresponding operator instruction has actually been displayed. Industrial controller usage as well as display update times each affect the time between the industrial controller generating the required operator instruction signal and the display of the signal associated with a given instruction of the industrial controller. As such, although the industrial controller has instructed that a signal be displayed to an operator, there may actually be a delay or lag between the industrial controller generating the instruction and the display communicating the instruction to an operator. Such lag results in inefficient operator interaction with the process controlled by the industrial controller and is not accounted for by performance monitoring systems.
Another consideration of controller performance monitoring is the comparison of process performance when different industrial controllers are utilized. That is, where it is desired to determine the operating efficiency of an industrial process when the process is operated with different control programs, it is often required to configure the industrial controller to operate with one control program and then reconfigure the industrial controller to operate with another control program. Comparing the performance of the industrial controller requires independently monitoring each industrial controller and inserting the performance monitoring programs into each of the respective control programs. Such performance monitoring is difficult to implement and suffers from the same inaccuracies addressed above with respect to the interference of the process system control by the monitoring system and non-confirmation of the display of the operator instructions.
Where one industrial controller program may provide a display instruction before another industrial controller program, the actual display of a signal associated with a given display instruction is not confirmed by the internal monitoring of the industrial controller program performance. The actual display of an operator instruction associated with a signal generated by the industrial controller may take place later under one controller program even though the signal associated with generation of the operator instruction is provided sooner as compared to another industrial controller program. As such, such monitoring systems have a tendency to provide information that is misrepresentative of the actual display of operator instructions. Accordingly, it is desired to provide an industrial controller performance monitoring system that confirms communication of a process signal to an operator. It is also desired to provide an industrial controller monitoring system that does not interfere with operation of the industrial controller being monitored to provide an accurate representation of non-monitored performance of the industrial controller.